Isolation Tool and Method

ABSTRACT

An isolation tool and method including a mandrel, a load ring, a large seal, at least two small seals, at least one slip, and a nose cone. The tool may include a slip backup, a level, a groove, at slip segments, a drilled hole, a nut such as a bridge plug nut, an interior flat section, an interior leveled section, and/or gripping material. The isolation tool is preferably a frac plug and the slip is preferably a composite slip.

BACKGROUND OF THE INVENTION Technical Field of Invention

The invention disclosed and taught herein relates generally to isolation tools for use in completion of an oil or gas well.

BACKGROUND OF THE INVENTION

In the completions process of an oil or gas well, there are multiple zones in the well that should be treated or fracked in order to improve production. These zones are at multiple depths in the wellbore and are designed to be treated individually or separate from one another. This separation of zones is accomplished by using some type of isolation tool that is lowered into the wellbore using various methods such as e-line or coiled tubing.

As the isolation tool is lowered to the desired depth, it is activated. Once activated, this isolation tool should be able to stay anchored in the desired position. A seal is then completed using various options of isolation tools and the zones are effectively isolated from each other and can then be treated. Once all zones are treated, these isolation tools are drilled back out and debris from the drill out flows to the surface.

A need exists for an isolation tool that has the capability to perform multiple functions by making minimal changes to the same tool on location when a different design and function is needed.

SUMMARY OF THE INVENTION

The present invention relate to an isolation tool known as a frac plug. This frac plug has the capability to perform multiple functions by making minimal changes to the same tool on location when a different design and function is needed. This design is capable of saving time and money by being versatile and interlocking during the drill out process.

The present invention relates to a multifunctional frac plug for use in isolating zones in a well bore. There is a need in the industry for a frac plug designed for multiple functions on location. It is desired that this frac plug be designed in a manner that eliminates the need to purchase multiple types of frac plugs to complete necessary operations in the field. It is also a desire in the industry to create a frac plug designed to lessen the necessity of presets and use less water when pumping down.

In the preferred embodiment, the isolation tool and the method of forming it includes a mandrel, a load ring, a large seal, at least two small seals, at least one slip, and a nose cone. The tool may include a slip backup, a level, a groove, at slip segments, a drilled hole, a nut such as a bridge plug nut, an interior flat section, an interior leveled section, and/or gripping material. The isolation tool is preferably a frac plug and the slip is preferably a composite slip.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a preferred embodiment of an isolation tool in the form of a frac plug.

FIG. 2 shows a cross-sectional, side view of a frac plug.

FIG. 3 is a cross-sectional, side view of a mandrel.

FIG. 4 is a cross-sectional, side view of a load ring.

FIG. 5 is a cross-sectional, side view of a slip.

FIG. 6 is a cross-sectional, side view of a slip backup.

FIG. 7 is a cross-sectional, side view of a small seal.

FIG. 8 is a cross-sectional, side view of a large seal.

FIG. 9 is a cross-sectional, side view of a nose cone.

FIG. 10 is a cross-sectional, side view of an embodiment of a nut.

FIG. 11 is a cross-sectional, side view of an embodiment of a nut.

FIG. 12 is a cross-sectional, side view of an embodiment of a nut.

FIG. 13 is a partial, perspective view of the gripping member in the form of a preferred embodiment of a composite slip.

FIG. 14 is a side view of a composite slip segment.

FIG. 15 is a front view of a composite slip segment.

FIG. 16 shows a cross sectional view of the composite slip.

FIG. 17 shows a top view of the composite slip.

FIG. 18 shows a side view of a preferred embodiment of an isolation tool.

FIG. 19 shows a cross-sectional, side view of the isolation tool.

DESCRIPTION OF THE DISCLOSED EMBODIMENTS

The drawings described above and the written description of specific structures and functions below are presented for illustrative purposes and not to limit the scope of what has been invented or the scope of the appended claims. Nor are the drawings drawn to any particular scale or fabrication standards, or intended to serve as blueprints, manufacturing parts list, or the like. Rather, the drawings and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding.

Persons of skill in this art will also appreciate that the development of an actual, real-world commercial embodiment incorporating aspects of the inventions will require numerous implementation specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation specific decisions may include, and likely are not limited to, compliance with system related, business related, government related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time consuming in an absolute sense, such efforts would nevertheless be a routine undertaking for those of skill in this art having the benefit of this disclosure.

It should also be understood that the embodiments disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Thus, the use of a singular term, such as, but not limited to, “a” and the like, is not intended as limiting of the number of items. Similarly, any relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like, used in the written description are for clarity in specific reference to the drawings and are not intended to limit the scope of the invention or the appended claims.

FIG. 1 shows a perspective view of a preferred embodiment of an isolation tool in the form of a frac plug 100 with components fully assembled. A frac plug 100 may include a variety of fiber and resin, metal alloys, epoxy, plastic or a combination of the listed materials. As shown, a mandrel 1 of the frac plug includes threads 9 on the outside diameter at one end 11 with holes 10 bored in that end 11 to accommodate shear screws. The mandrel 1 is preferably designed to receive a frac ball in that end 11 and has threads to receive a caged ball or nut 7 such as a bridge plug nut in the end 11.

As shown in FIG. 2 a cross-sectional, side view of the frac plug 100, the mandrel 1 preferably has a through bore completely through an inside diameter and is threaded in the inside diameter 13 of the other end 12 to receive a nut 7 such as a ball drop nut or bridge plug nut. The mandrel 1 is also threaded on the outside diameter 14 of the other end 12 to receive the threaded nose cone 8.

As shown in FIGS. 1 and 2, a load ring 2 is engaged by sliding onto the mandrel 1 at the end 11. A slip 3 a is adjacent to the load ring 2. A slip backup 4 a is adjacent to the slip 3 a. A small seal 5 a is adjacent to the slip backup 4 a. A large seal 6 is adjacent to the small seal 5 a and a second small seal 5 b. A slip backup 4 b is adjacent to the small seal 5 b. A slip FIG. 3b is adjacent to the slip backup 4 b. A ball drop nut 7 is threaded and engaged into end 12 of mandrel 1. A nose cone 8 is threaded and engaged onto the end 12 of mandrel 1 and is adjacent to the slip FIG. 3 b.

FIG. 3 is a cross-sectional, side view of the mandrel 1. The mandrel 1 preferably has a trough bore completely through an inside diameter and is threaded in the inside diameter 13 to receive a nut 7 such as a ball drop nut or bridge plug nut shown in FIGS. 1 and 2. The mandrel 1 is also threaded on the outside diameter 14 to receive the threaded nose cone 8 shown in FIGS. 1 and 2.

As shown, there are also threads 9 on the other end of the mandrel 1 that are shown as end 11 of frac plug 100 in FIGS. 1 and 2. The holes 10 that may be formed or drilled in mandrel 1 are shown in FIG. 1.

FIG. 4 is a cross-sectional, side view of the load ring 2. The load ring 2 may be round in shape and can have a flat space on the inside diameter 15 of the load ring 2 as well as having an angled surface 16 on the inside diameter of the load ring 2. The load ring 2 can engage with the mandrel 1 of by sliding. The load ring 2 may be designed to withstand the force applied by a desired setting tool to compress the components during the setting process. The load ring 2 may also have a number of holes 17 a, 17 b drilled through the thickness of the load ring 2 to receive a set screw.

FIG. 5 is a cross-sectional, side view of the slip 3, shown as slips 3 a, 3 b in FIGS. 1 and 2. Each slip 3 may have an outside diameter of preferably about 2.5 inches to preferably about 7 inches. The slip 3 may also have an inside diameter of preferably about 2 inches to preferably about 6.5 inches. The slip 3 may have levels milled into the slip 3 to allow the slip 3 to separate into sections and expand.

The slip 3 as depicted has leveled edges 19 on the outer surface of the outer diameter at varying angles that are designed to engage with the casing and secure the frac plug 100 inside the casing. The slip 3 may have a holes 20 drilled into the slip 3 which may have a diameter of preferably about 0.125 inch to preferably about 0.5 inch with a depth completely through the body of the slip 3 or a depth of preferably about 0.290 inches as shown herein. The slip 3 also may have relief grooves 18 milled radially into the inside diameter of the slip 3 at determined depths and locations.

The slip 2 may have a flat surface 21 on the inside diameter of a determined length and a leveled surface 22 on the inside diameter with an angle ranging from preferably about 45 degrees to preferably about 20 degrees. The slip 3 may also have second relief grooves 23 milled into the surface of the slip segments 3 and into the milled areas between the slip segments 3 to allow to break into smaller pieces during the drill out process.

FIG. 6 is a cross-sectional, side view of the slip backup 4, shown as slip backups 4 a, 4 b in FIGS. 1 and 2. The slip backup 4 may have an outside diameter of preferably about 2 inches to preferably about 7 inches and an inside diameter of preferably about 1.5 inches to preferably about 6.5 inches. The slip backup 4 may have a length of preferably about 2 inches to preferably about 6 inches.

The slip backup 4 can have a flat surface 24 on the outside diameter and a leveled surface 25 on the end with angles ranging from preferably about 20 degrees to preferably about 45 degrees. The slip backup 4 may have slots cut 26 into the body with a depth of preferably about 1 inch to preferably about 2 inches and a width of preferably about 0.05 to preferably about 0.25 inches and may have as many as preferably about 4 to preferably about 12 slots. The slip backup 4 may have a number of holes 27 with a diameter of preferably about 0.125 inches to preferably about 0.25 inches drilled through the body to receive a set screw. The leveled surface 25 of the slip backups 4 a, 4 b are adjacent to the slips 3 a, 3 b shown in FIGS. 1 and 2.

FIG. 7 is a cross-sectional, side view of the small seal 5, shown as small seals 5 a, 5 b in FIGS. 1 and 2. The small seal 5 is preferably a seal made of an elastomer, a polytetrafluoroethylene material including synthetic fluoropolymer of tetrafluoroethylene materials such as but not limited to the product sold under the trade name Teflon®, plastic, or other malleable material. The seal 5 may have an outside diameter of preferably about 2 inches to preferably about 7 inches and an inside diameter of preferably about 1.5 inches to preferably about 6.5 inches.

The small seal 5 may have a flat surface 28 on the surface of the seal and a leveled surface 29 with angles ranging from preferably about 20 degrees to preferably about 40 degrees on the outside diameter. The small seal 5 may also have an overall length of preferably about 1.5 inches to preferably about 6 inches. The small seal 5 may have a flat surface 31 in the inside diameter adjacent to the leveled surface 30 of the inside diameter. From that flat surface 31 on the inside diameter, the small seal 5 may have the leveled area 30 on the inside diameter at angles ranging from preferably about 20 degrees to preferably about 45 degrees, extending outwardly.

FIG. 8 is a cross-sectional, side view of the large seal 6. The large seal 6 may be made from an elastomer, a polytetrafluoroethylene material including synthetic fluoropolymer of tetrafluoroethylene materials such as but not limited to the product sold under the trade name Teflon®, plastic, or another malleable material. The large seal 6 may be preferably about 2 inches to preferably about 7 inches in length and may have an outside diameter of preferably about 2 inches to preferably about 7 inches along with an inside diameter of preferably about 1.5 inches to preferably about 6.5 inches.

The large seal 6 may have a flat surface 32 on the outside diameter, extending preferably about 2 inches to preferably about 6 inches in the center of the outside diameter, adjacent to a leveled portion 33 of the large seal. The large seal 6 may have a leveled areas 33 on the outside diameter with angles ranging from preferably about 20 degrees to preferably about 45 degrees. The large seal 6 illustrates a flat portion 34 on the inside diameter of the large seal 6, extending to the leveled portion 35 in the inside diameter. The leveled portion 35 of the inside diameter on the large seal 6 may have a level or radius of preferably about 20 degrees to preferably about 45 degrees.

FIG. 9 is a cross-sectional, side view of the nose cone 8. In a preferred embodiment, the nose cone 8 is detachable, and is threaded and capable of engaging with the mandrel 1 shown in FIGS. 1, 2, and 3. The nose cone 8 is preferably conical in shape and can be preferably about 2 inches to preferably about 7 inches in diameter.

The nose cone 8 has a flat section 36 on the surface and a tapered off section 37 to a level of preferably about 60 degrees to preferably about 90 degrees. The outside diameter of the nose cone 8 may have a recessed area 38 to accommodate a pump down ring. The nose cone 8 depicts threads 39 in the inside diameter that can be engaged with the outside diameter threads 14 of the end one of the mandrel 1. The inside diameter of the nose cone 8 also has threads 40 designed to engage with the threads 9 of end 11 of the mandrel 1. The nose cone 8 may also have preferably about 2 to preferably about 4 holes 41 drilled in the nose cone. These holes 41 may have a diameter of preferably about 0.25 to preferably about 0.5 inches.

FIG. 10 is a cross-sectional, side view of the nut 7. As depicted, the nut 7 is a bridge plug nut. The nut 7 can be made of brass, aluminum, composite, bronze, or a mixture of the listed materials. The nut 7 may be preferably about 2 inches to preferably about 4 inches in length and have an outside diameter measuring preferably about 1 inch to preferably about 4 inches.

The nut 7 has threads on the outside diameter of end 42 of the nut 7 and is solid on end 43 of the nut 7. The nut 7 may have threads in the inside 44. The nut 7 preferably has a first chamber 45 extending past the inside 44. The first chamber 45 typically has a larger inside diameter than that of the inside 44. The nut 7 preferably also has a second chamber 46 containing smaller inside diameter that extends past the first chamber 45, creating a stopping point for a setting rod.

FIG. 11 is a cross-sectional, side view of the a different embodiment of the nut 7. As depicted, FIG. 11 shows a ball drop nut. The nut 7 can be made of brass, aluminum, composite, bronze, or a mixture of the listed materials. The nut 7 may be preferably about 2 inches to preferably about 4 inches in length and can have an outside diameter of preferably about 1 inch to preferably about 4 inches.

The nut 7 has threads on the outside diameter of end 47 and has a hole drilled through the body to receive a threaded rod composed of composite, aluminum, brass, or a mixture of the listed materials. This rod is screwed into position after placing an preferably about 0.625 inches or preferably about ⅝-inch ball into the inside diameter of the nut, creating a ball drop nut. The ball drop nut 7 has threads that can be sheared on the inside diameter of the nut, extending to a first chamber 48 that has a larger inside diameter. The first chamber 48 extends to a second chamber 49 with a smaller inside diameter, creating a stopping area for the setting rod. Adjacent to the second chamber 49, the ball drop nut 7 has a hole 50 bored completely through the inside diameter to allow fluid to flow through the nut 7.

FIG. 12 is a cross-sectional, side view of the a different embodiment of the nut 7. As depicted, the nut 7 is a caged ball nut that can be made of composite, brass, aluminum, or a mixture of the listed materials. The caged ball nut 7 can be preferably about 2 to preferably about 6 inches in length and preferably about 1 to preferably about 4 inches in diameter. The nut 7 has a smaller outside diameter of preferably about 1.220 inches which extends preferably about 0.790 inches in length.

There are shown two grooves 51 cut into this flat area 52 to receive O rings. From the stopping point of the smaller inside diameter of end 53, there is a level 54 angled at preferably about 20 to preferably about 24 degrees that extends to the outside diameter of the nut 7. There are threads 55 on the outside diameter of the nut that match the threads on the inside diameter of the mandrel 1 depicted in FIGS. 1-3. The caged ball nut 7 has a hole 56 drilled completely through the body of the nut 7.

After inserting a ball made of composite, brass, aluminum, or a mixture of the listed materials, a rod is placed through the body to hold the ball in place. The caged ball nut 7 has a trough bored completely through the body of the nut 7 creating a flow passage for fluid. The inside diameter of the nut can be preferably about 0.531 to preferably about 1 inch in the first chamber 57.

Adjacent to the first chamber 57, the second chamber 58 has a larger inside diameter of preferably about 0.75 inches. Adjacent to the second chamber 58, the third chamber 59 opens up to an inside diameter of preferably about 1.143 inches. This creates a stopping area for the setting rod. The caged ball nut 7 can also be converted into a bridge plug nut by leaving the first chamber 57 solid.

FIG. 13 is a partial, perspective view of the gripping member. In this preferred embodiment, the gripping member is a composite slip 3. As shown, the composite slip 3 includes segments 61 that are connected together to form a full composite slip 3 as shown in FIGS. 16 and 17.

FIG. 14 is a side view of a composite slip segment 61. It is preferable for each composite slip 3 to be coated with a gripping material. The composite slip segment 61 shown in FIG. 14 is coated with about 0.055 inches of a gripping material. Suitable gripping materials include coatings, bonding agents, or encasement particles that may be formed from a non-destructive material such as abrasive powders, grains, elastomers, hard stones, or other materials.

Gripping members or slips can be singular, or have a multitude on one tool. a couple of examples would be the slips on liner hangers or a packer that uses a slip or type of gripping member to hold it in a desired place. Other tools that could benefit from the gripping members might be an isolation tool capable of running through a very small inside diameter and once in place, then having the capability to expand and be secured in a much larger inside diameter. The possibility also exists that this non-destructive slip or gripping member be incorporated into a process that is used to lower coiled tubing, conventional pipe downhole so as to lessen the destruction done to the pipe in the process.

FIG. 15 is a front view of a composite slip segment 61. Holes 62 are drilled in at a desired depth on the exterior surface 63 of the composite slip segment 61. These holes 62 are drilled for the gripping material to penetrate the composite slip surface 63 to desired depth and create anchors into the composite slip segment 61.

FIG. 16 shows a cross sectional view of the composite slip 3. The composite slip 3 shows the composite slip exterior surface 69 of the composite slip segments 61 having a flat surface. The right end 64 of the composite slip 3 as displayed is shown with an interior flat surface section 65. In a preferred embodiment, this flat surface section 65 has a diameter of about 3.125 inches. The interior flat surface section 65 is adjacent to an interior leveled area 66 that flares to the left end 67 of the composite slip 3 as shown. In a preferred embodiment, this leveled area 66 can have an angle ranging from about 20 to about 45 degrees. In a preferred embodiment, the outside diameter of the composite slip 3 is about 3.627 but can have an outside diameter of about 2 inches to about 7 inches in length. The composite slip exterior surface 69 of the outside diameter of the composite slip 3 preferably has three flat surfaces spaced with relief grooves 68 between each section.

FIG. 17 shows a top view of the composite slip 3. The composite slip 3 preferably includes drilled shear pin holes 70 drilled in each segment 61 to be desired depth that accommodate shear pins. The shear pins used in each section may be made of composite, brass, bronze, aluminum, or a mixture of the listed materials.

FIGS. 18 and 19 show the isolation tool 100 using this preferred embodiment of the gripping member as composite slips 3 a and 3 b and are similar to the embodiment of the isolation tool 100 depicted in FIGS. 1 and 2, respectively.

While the invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the description. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention. 

What is claimed is:
 1. An isolation tool comprising: a mandrel; a load ring; a large seal; at least two small seals, wherein each small seal is adjacent to the large seal; at least one slip; and a nose cone.
 2. The isolation tool of claim 1 wherein the isolation tool is a frac plug.
 3. The isolation tool of claim 1 wherein the slip is a composite slip.
 5. The isolation tool of claim 1 further comprising at least one slip backup.
 6. The isolation tool of claim 1 wherein the slip further comprises at least one level milled into the slip.
 7. The isolation tool of claim 3 wherein the slip further comprises at least one second relief groove milled into a surface of the slip.
 8. The isolation tool of claim 1 further comprising a nut selected from the group consisting of a bridge plug nut, a ball drop nut, and a caged ball nut.
 9. The isolation tool of claim 1 further comprising gripping material.
 10. The isolation tool of claim 1 wherein the slip comprises at least two segments, wherein each segment further comprises: a segment exterior surface; and at least one drilled hole in each segment exterior surface.
 11. The isolation tool of claim 10, further comprising at least one groove formed in the exterior segment surface.
 12. The isolation tool of claim 10, wherein the slip further comprises: an interior flat surface section; and an interior leveled surface section.
 13. The isolation tool of claim 1, wherein the slip further comprises drilled shear pin holes.
 14. A method of forming an isolation tool comprising the steps of: (a) connecting at least one load ring on a mandrel; (b) connecting at least one slip adjacent to the load ring; (c) connecting at least one slip backup adjacent to the slip; (d) connecting at least one small seal adjacent to the slip backup; (e) connecting at least one large seal adjacent to the small seal.
 15. The method of claim 14 further comprising the steps of: (f) connecting at least one nose cone.
 16. The method of claim 14 wherein the isolation tool is a frac plug.
 17. The method of claim 15 further comprising the step of: (g) fastening the nose cone in place with a nut.
 18. The method of claim 18 wherein the nut is selected from the group consisting of a bridge plug nut, a ball drop nut, and a caged ball nut.
 19. The method of claim 14, wherein the slip in Step (b) is a composite slip.
 20. The method of claim 14, further comprising applying gripping material to the slip before Step (b). 